1. Field of the Invention
The present invention relates to an LED circuit having an LED array structure capable of being changed according to a level of input voltage.
2. Description of the Related Art
Alight emitting diode (LED) is a semiconductor device that is configured as a p-n junction structure and emits light by the recombination of electrons and holes. The light emitting diode may be manufactured to have a small size while having excellent monochromatic peak wavelength and light efficiency and may be manufactured in an environmentally-friendly way, while having reduced power consumption, or the like. For this reason, the light emitting diode has rapidly replaced existing lighting devices.
In general, the light emitting diode is driven by a DC voltage of several volts. Therefore, a circuit for driving the existing light emitting diode mainly uses a scheme in which commercial AC voltage is rectified and then constant current is supplied to a light emitting device using a converter such as a flyback converter.
The driving circuit essentially includes a smoothing capacitor. The smoothing capacitor has a short lifespan, such that the lifespan of the lighting device using the light emitting diode may be shortened.
In addition, existing LED circuit drives the light emitting diode by using only a rectified waveform so as not to use the smoothing capacitor, and cannot drive all light emitting diodes at a predetermined voltage or less and is thus inefficient.